Much effort is presently focused toward providing distributed processing in computer networks. Distributed processing provides improved efficiency in networks by balancing loads between computers that are congested and those which have spare capacity. Users might, for example, offload particularly time consuming tasks, such as text formatting or floating point calculations, from their home computers to computers specially adapted for such tasks.
A method of performing remote process execution in a network is fully described in our copending U.S. patent application Ser. No. 796,863, entitled "Method of Distributed Processing in a Computer Nework." The disclosure of the application is incorporated in its entirety herein.
In a network in which resource sharing is allowed, there usually is some notion at each computer of which other network computers may act as resources for this computer.
Some systems provide a centralized resource name serving service at a single computer in the network. A computer transmits a query to the single computer to find out with which other computers it may share resources. If the single computer becomes faulty, network resource sharing and name serving is out of business. Another disadvantage of this centralized scheme is that an additional reference is required to the central computer before further processing can be continued. For these and other reasons, some networks use a distributed name serving function. The LOCUS system, described by G. Popek et al in "A Network Transparent High Reliability Distributed System", Proceedings of ACM-SIGOPS 8th Symposium on Operating Systems Principles, December 1981, pages 169-177, is an example of a virtual centralized name server. It conditions a network of computers to simulate a single virtual computer. This technique undesirably sacrifices much of the autonomy of having individual network computers.
Another centralized name server is disclosed by M. Solomon et al in "The CSNET Name Server", North-Holland Publishing Company; Computer Networks 6 (1982); pages 161-172. However, this system mitigates some of the problems of a centralized server by cacheing some of the server information at the individual computers as the information is received.
"The Clearinghouse: A Decentralized Agent for Locating Named Objects in a Distributed Environment", ACM Transactions on Office Information Systems, Vol. 1, No. 3, July 1983, discloses a distributed system. I. Gertner and R. Lindenberg describe another partially distributed database name server in a ring topology network in their article, "Initializing Replicated Name Servers in a Wide Area Network".
The distributed name servers mentioned above each incorporate extremely complicated algorithms to update the individual databases to changes in the network. Problems that must be addressed in some way include what to do when a computer is added to the network, how to insure consistency in parts of the distributed database that are replicated, how to know that a server has become inoperative, how to inform the clients of this situation, what to do when a server comes back on-line, etc.
U.S. Pat. No. 4,423,414, issued to D. M. Bryant et al on Dec. 27, 1983, attempts to solve some of the above problems by using a broadcast scheme in a network. A prospective client process wishing to execute a procedure remotely broadcasts a message identifying the procedure to the network. Computers recognizing the procedure respond. The first to respond is selected.